The phrase ‘Wag the Dog’ is used to indicate that attention is purposely being diverted from something of greater importance to something of lesser importance.

Example of Use: “He’s wagging the dog to keep you from discovering the truth about a situation that is much more dire.”

The term ‘wag the dog’ comes from the expression that a dog is smarter than its tail, but if the tail were smarter than the dog, the tail would be in control.

From UsingEnglish.Com

To ‘wag the dog’ means to purposely divert attention from what would otherwise be of greater importance, to something else of lesser significance. By doing so, the lesser-significant event is catapulted into the limelight, drowning proper attention to what was originally the more important issue.

From TheIdioms.com

to divert attention from something that is bad

to change the topic from something that is more important to something that is not

to hide something

a small part (of something) controlling the big part

The prime minister keeps wagging the dog to keep people from actually finding out about the scam and its details

I had to wag the dog so that he does not find out where I had actually gone this afternoon

The management wags the dog when it comes to the truth about the business